Influences of synthesizing temperatures on the properties of Cu2ZnSnS4 prepared by sol–gel spin-coated deposition

In this work Cu2ZnSnS4 (CZTS) suitable for the absorption layer in solar cells was successfully prepared by sol–gel spin-coated deposition. CZTS precursors were prepared by using solutions of copper (II) chloride, zinc (II) chloride, tin (IV) chloride, and thiourea. Texture structures with kesterite crystallinity reflected from the X-ray diffraction of (112), (200), and (312) planes of the CZTS were obtained as synthesized at a temperature of over 240 °C. The absorption coefficients of the CZTS films are higher than 104 cm−1, and the optical-energy gap is about 1.5 eV. Without sulfurization treatment, a near stoichiometry composition of the CZTS is obtained at a synthesizing temperature of 280 °C.